In brackish water aquaculture fish diseases are not so commonly encountered as in fresh water aquaculture. Diseases of fin and shell-fishes recorded from brackishwater impoundments are as follows.
Causative organism of the disease is Vibrio parahaemolyticus. The disease is generally recorded in shrimps. The symptoms of the disease are expansion of chro-matophores and excessive opaqueness of abdominal muscles. Predisposing factors for the disease are over stocking and capture.
Causative organisms of the disease are Vibrio sp. and Pseudomonas sp. The common symptoms of the disease are brown spots on the exoskeleton, often with white margine and necrosis of the underlying tissue. The disease is encountered mostly from Penaeus spp
Following parasites have also been recorded from the brackish water fishes :-
|Lates calcarifer||Ergasilus sp.|
|Lates calcarifer||Trichodina sp.|
|Mystus gulio||Echinorhynchus sp.|
Non-parasitic diseases can be controlled by thining out the population and providing supplementary feed. Soft shell and muscle opaqueness of P. monodon also occur due to sudden fluctuation of temperature (due to hail storm) and salinity of water (due to rains) or repeated netting. However, soft shell diseases can be controlled by repeated liming. More emphasis should be laid in maintaining general hygiene of fish pond.
- Central Inland Fisheries Research Institute, Barrackpore